1. Field of the Invention
The invention relates to a method and an apparatus for judging a depth of anesthesia and raising an alarm.
2. Related Art
When a patient in sickness is to undergo an operation or a test, anesthesia is previously given to the patient. Conventionally, there is no apparatus which can correctly measure or judge the depth of anesthesia. In fact, after anesthesia is given to the patient, therefore, the doctor measures parameters such as the blood pressure, and the respiration and empirically presumes the depth of anesthesia, and thereafter the patient undergoes the operation or the test.
From the standpoint of the patient, the judgement whether the depth of anesthesia is sufficient or not is important. When the depth of anesthesia is sufficient in general anesthesia, for example, the patient is unconscious and does not feel a pain due to incision by using a knife. Therefore, the patient cannot hear discussions between the doctor and the nurse, so that the patient does not feel apprehension about the discussions and their movement.
By contrast, when the depth of anesthesia is insufficient, the patient feels pain in the incision region, or the patient is conscious. Under this state, since the patient is conscious, the patient feels apprehension about the operation. During the operation, particularly, the patient is in the state where the patient cannot move and utter, and hence cannot tell the doctor or the nurse that the anesthesia is insufficient. It seems that, since the patient is conscious, the patient feels even fear under the state where the patient is very sensitive to surrounding discussions and movement of the doctor and the nurse engaging, in the operation. An instance in which an operation was carried out while the depth of anesthesia was insufficient and the patient was conscious has been reported.
Recently, in order to reduce the effect of administration of an anesthetic agent on a living body, there is a tendency to perform an operation with administration of an anesthetic agent of the minimum level. Consequently, an apparatus or a method which can correctly judge a depth of anesthesia will play an important role, and hence it is requested to early develop such an apparatus or a method.
As described above, however, an apparatus which can correctly measure or judge the depth of anesthesia in administration of an anesthetic agent is not available at present.